The researchers have found that honey bees show a remarkable ability to spot the same human face even days after training.

The training consisted of showing the bees the very same series of black-and-white pictures of faces that are used to test human memory. The bees got tasty or sour rewards for choosing correctly and incorrectly.

The newfound bee ability is likely connected to their ability to recognise different flowers, says Dyer.

On the other hand, the discovery is one of a long string over the last decade about various animals which all point to one startling revelation: It doesn't take a huge human brain or even a mammalian brain to recognise individual human faces or do a lot of other complex tasks.

"The more we study these creatures, the more we find they have abilities like ours," says insect vision researcher Professor Mandyam Srinivasan of Australian National University in Canberra.

From bees to wasps, spiders and even sheep, other animals have proven they can not only recognise our faces, but they navigate mazes, match objects and shapes and even associate smells with previous experiences.

"Sometimes I wonder what we are doing with two-kilogram brains," muses Srinivasan.

Bees, for their part, have brains about 20,000 times less massive than the human brain.

Implications

The larger implications of such a small number of neurons doing such complex tasks are intriguing, but not obvious, says Dyer.

There is the possibility, for instance, that someday humans who have experienced brain damage could borrow the honey bee trick - whatever the trick is - to relearn facial recognition and other lost abilities, he says.

There are also big implications for the security industry and artificial intelligence, Srinivasan points out.

"Face recognition is such a hard thing," he says. "People are still working on it for computer and security systems."

The honey bee experiment implies there is a simpler solution to the problem that artificial intelligence researchers haven't yet hit on, he says.

Implications aside, Dyer admits that his new study does seem a bit strange at first glance. In fact, that's why he and his colleagues had to sneak the bee experiment in at the tail end of another experiment at Queen Mary College in London, he says.